The invention relates to the treatment of internal parasites and protozoa, especially in humans. In one aspect, the invention relates to an improved treatment of parasitic, including protozoic, infections in humans using an extract of oregano.
Parasitic infections have a long history as a cause of disease in humans and animals. These include protozoan parasites such as extra-intestinal amoebas, toxoplasmas and trichomonas. In addition to protozoa, other human parasites include helminths such as roundworm, pinworm, hookworm, shisasomes and tapeworm. Pathogenic protozoa, such as Giardia lamblia, Entamoeba histolytica, Dientamoeba fragilis, Cryptosporidium parvum, Cyclospora cayetanensis as well as Blastocystis hominis, are recognized as pathogenic organisms. See Gugliemetti P et al, Family outbreak of Blastocystis hominis associated with gastroenteritis, Letter, Lancet 1989,vol. 2, 1394; Udkow MP et al., Blastocystis hominis: Prevalence in asymptomatic versus symptomatic hosts, JID 1993, 168:242-4; Zierdt CH, Blastocystis hominis, Past and Future, Clin Microbiol Rev 1991; 4:61-79; Wilson K, et al., Blastocystis hominis infection: signs and symptoms in patients at Wilford Hall Medical Center, Military Med 1990; 155:394-6; Waghorn DJ, et al: Clinical significance of Blastocystis hominis. Letter. Lancet 1991: 337:609; O'Gorman M. et al: Prevalence and characteristics of Blastocystis hominis infection in children, Clinical Pediatrics, 1993; 32:91-96.
Certain intestinal parasites are not generally considered to cause symptoms in those with robust immune systems. In this category are Entamoeba nana, E. hartmanni, Entamoeba coli, Endolimax nana and Enteromonas hominis. Nonetheless, the presence of multiple intestinal parasites may indicate a compromised immune system, imbalanced gut flora and/or abnormal digestive function, such as hypochlorhydria. Treatment is at the discretion of the physician. See Garaveli PL et al. , "Blastocystis: a new disease in the acquired immunodeficiency syndrome," International J STD & AIDS 1990; 1:134-135.
Many parasites that reside in the gastrointestinal tract cause gastrointestinal signs and symptoms, such as abdominal pain, bloating, diarrhea, and secondary carbohydrate intolerances including lactose intolerance and unexplained weight loss. See Jones JE, Signs and symptoms of parasitic disease, Primary Care 1991; 12:1-12. In some cases infection by intestinal parasites becomes self-limiting; in other cases parasites can cause chronic infection with intermittent symptoms that can persist indefinitely until treated. Parasites such as E. histolytica can penetrate the gut mucosal barrier, leading to infections of specific organs or to systemic infection. These may be more difficult to eliminate.
The prevalence of various parasitic infections in the U. S. reflects multiple factors. Lifestyle, purity of domestic water supplies, and state of an individual's immune system are keys. The fecal-oral route of infection is common and poor hygiene among food handlers has increased the prevalence in some areas. Contamination of municipal water supplies by agricultural run-off, together with ineffective water treatment have caused localized epidemics.
Treatment of parasitic infections typically relies on a series of medications including tinidazole, metronidazole, quinacrine hydrochloride, iodoquinol and similar compounds. These can have significant side effects, as cited in the Physicians'Desk Reference , 49.sup.th Edition, Medical Economics Data Production Co. 1995,including pages 1114, 2199, 2322-2324.
Botanical preparations offer an alternative approach to treatment. Herbs have been used in folk medicine for centuries for diarrhea and gastrointestinal upsets. However, culinary herbs are cited for their antioxidant, antibacterial and antifungal properties most often in the context of food preservation, but not as antiparasitics. See Azzouz MA et al. , "Comparative antimycotic effects of selected herbs, spices, plant components and commercial antifungal agents," J Food Protection 1982; 45:1298-1301; Conner DE, et al. , Effects of essential oils from plants on growth of food spoilage yeasts, J Food Science 1984; 49: 429-34; Lagouri V et al. , Nutrient antioxidants of oregano. Int J Food Sci Nutr 1996; 47:493-7.
In particular, oregano (Oreganum vulgare, Mediterranean oregano) a common culinary herb, and its associated essential oil have been shown to inhibit the growth of many kinds of bacteria. See Belaiche P, Traite de Phytotherapie et d'Armoatherapie, Tome 1. L'Aromatogramme, Maloine SA Editeur, 1979, pp 92-100.
In addition, the oil of oregano is a potent inhibitor of yeast and fungi, including the potential pathogen, Candida albicans. See Stiles JC et al. , The inhibition of Candida albicans by oregano, J Applied Nutr 1995; 47:96-102; Sivropoulou A et al. , Antimicrobial and cytotoxic activities of Origanum essential oils, J Agric Food Chem 1995; 44: 1202-1205.
There are no previous reports documenting the use of oregano (Oreganum vulgare) in the treatment of parasites in the scientific literature. A single report cites "oregano" in the context of inhibition of Giardia lamblia trophozytes in culture. See Ponce-Macotela M et al. , "Efecto antigiardiasico in vitro de 14 extractos des plantas", Rev Invest Clin 1994; 46:343-7. Ponce-Macotela et al studied extracts of plants typically used in Mexico as antidiarrheals and/or antiparasitics. However, the particular plant they refer to as oregano was Lipia beriandieri, which belongs to the Lippia genera, and not Oreganum vulgare. These investigators did not systematically study patients to determine whether in fact parasites could be eradicated by treatment.